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| {{Infobox_Disease | | {{Asplenia}} |
| | Name = Asplenia
| | {{CMG}}{{AE}} {{Kalpana Giri}} |
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| | DiseasesDB =
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| | ICD10 = {{ICD10|D|73|0|d|70}}, {{ICD10|Q|89|0|q|80}}
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| | ICD9 = {{ICD9|289.59}}, {{ICD9|759.01}}
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| | OMIM = 208530
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| | OMIM_mult = {{OMIM2|%271400}} {{OMIM2|208540}}
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| ==Overview==
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| '''Asplenia''' refers to the absence ('a-') of normal [[spleen]] function and is associated with some serious infection risks. '''Hyposplenism''' is used to describe reduced ('hypo-') splenic functioning, but not as severely affected as with asplenism.
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| ==Causes== | | ==[[Asplenia overview|Overview]]== |
| Asplenia may rarely be a [[congenital disorder|congenital]] due to genetic disorders or exposure to environmental factors during gestation.<ref>{{cite journal |author= |title=A 3-Month-Old With Sepsis |work=New Orleans Citywide Rounds |journal=Infect Med |year=1999 |volume=16 |issue=5 |pages=311-316 }} - [http://www.medscape.com/viewarticle/417489_4 Final Diagnosis and Discussion]</ref> More commonly it is [[Acquired disorder|acquired]] through surgery ([[splenectomy]]) or through processes that destroy the spleen, generally through its function to filter the blood and therefore referred to as [[autosplenectomy]] (eg [[spherocytosis]] and [[sickle-cell disease]]).
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| ==Natural History, Complications and Prognosis== | | ==[[Asplenia historical perspective|Historical Perspective]]== |
| ===Complications===
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| Asplenia increases the risk of [[septicaemia]] from encapsulated bacteria, and can result in a syndrome known as [[overwhelming post splenectomy infection]] (OPSI) which can kill within a few hours. In particular patients are at risk from [[Pneumococcus]], but also ''[[Haemophilus influenzae]]'' & [[Meningococcus]].
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| The risk to asplenic patients has been expressed as equivalent for a child to die in home accident, and for adults dying in a road traffic accident (reference UK Splenectomy Trust Advice) - so sensible precautions are needed, but no panic.<!--
| | ==[[Asplenia classification|Classification]]== |
| --><ref>{{cite web | title=Splenectomy and Infection | url=http://www.ekpt.nhs.uk/pdf/PILs/EKHT_Leaflets/Splenectomy_and_Infection.pdf | format=PDF | date=March 2002 | publisher=Splenectomy Trust | accessdate=2006-12-12}} - reprint from Kent and Medway NHS and Social Care Partnership Trust</ref>
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| ==Treatment== | | ==[[Asplenia pathophysiology|Pathophysiology]]== |
| ===Medical Therapy===
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| To minimise the risks, antibiotic & vaccination protocols have been established,<!--
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| --><ref name="BMJ1996">{{cite journal | author= | title=Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen. Working Party of the British Committee for Standards in Haematology Clinical Haematology Task Force | journal=BMJ | year=1996 | pages=430-4 | volume=312 | issue=7028 | id=PMID 8601117 | url=http://bmj.bmjjournals.com/cgi/content/full/312/7028/430}}</ref><!--
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| --><ref name="BMJ2001">{{cite journal | author=J M Davies et al | title=The Prevention And Treatment Of Infection In Patients With An Absent Or Dysfunctional Spleen - British Committee for Standards in Haematology Guideline up-date | journal=BMJ | year=2001-06-02 | url=http://bmj.bmjjournals.com/cgi/eletters/312/7028/430#12088}}</ref> <!--
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| -->but are often poorly adhered to by doctors and patients.<!--
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| --><ref name="JCP2000">{{cite journal | author=Waghorn DJ | title=Overwhelming infection in asplenic patients: current best practice preventive measures are not being followed | journal=J Clin Pathol | year=2001 | pages=214-8 | volume=54 | issue=3 | id=PMID 11253134 | url=http://jcp.bmjjournals.com/cgi/content/full/54/3/214}}</ref>
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| ====Antibiotic prophylaxis==== | | ==[[Asplenia causes|Causes]]== |
| Because of the increased risk of infection, physicians administer oral antibiotics as a [[prophylaxis]] after a surgical splenectomy. The duration suggested varies: one suggestion is that antibiotics be taken for two years or until the age of sixteen years old is reached, whichever is longer.
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| Patients are also cautioned to start a full-dose course of antibiotics at the first onset of an [[upper respiratory tract infection|upper]] or [[lower respiratory tract infection]] (for example, sore throat or cough), or at the onset of any fever.
| | ==[[Asplenia differential diagnosis|Differentiating Asplenia from other Diseases]]== |
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| ====Vaccinations==== | | ==[[Asplenia epidemiology and demographics|Epidemiology and Demographics]]== |
| It is suggested that splenectomized persons receive the following vaccinations, and ideally prior to planned splenectomy surgery:
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| *[[pneumococcus]] every 6 years (a conjugated form is used for children under 2 years)
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| *''[[Haemophilus influenzae]]'' - whilst in many countries now routinely given to all children, a single booster is advised following the development of asplenia, but for those adults who have not been previously vaccinated, two doses given two months apart were advised in the new 2006 UK vaccination guidelines (in the UK may be given as a combined Hib/MenC vaccine).<ref name="GreenBook">{{cite book |author=Joint Committee on Vaccination and Immunisation |editor=Editors Salisbury D, Ramsay M, Noakes K |title=Immunisation Against Infectious Disease 2006 |url=http://www.dh.gov.uk/en/Policyandguidance/Healthandsocialcaretopics/Greenbook/DH_4097254 |chapter=Chapter 7 : Immunisation of individuals with underlying medical conditions |chapterurl=http://www.dh.gov.uk/prod_consum_dh/idcplg?IdcService=GET_FILE&dID=115681&Rendition=Web |format=PDF |publisher=Stationery Office |location=Edinburgh |date=21 December 2006 |pages= |isbn=0113225288 |oclc= |doi= }} - ''see pages 50-1 and table 7.1''</ref>
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| *[[meningococcus]]-'C' conjugate vaccine - again routinely given to children in many countries, previously vaccinated adults require a single booster and non-immunised adults advised, in UK since 2006, to have two doses given two months apart.<ref name="GreenBook"/>
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| *annual [[influenza|flu]] vaccinations - to help prevent getting secondary bacterial infection.
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| ====Travel measures==== | | ==[[Asplenia risk factors|Risk Factors]]== |
| In addition to the normal immunisations advised for the countries to be visited, Group A meningococcus should be included if visiting counties of particular risk (e.g. sub-saharan Africa). The non-conjugated Meningitis A&C vaccines usually used for this purpose give only 3 years coverage and provide less-effective long-term cover for Meningitis C than the conjugated form already mentioned.
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| Those lacking a functional spleen are at higher risk of catching [[malaria]] and dying from this. Travel to malarial areas will carry greater risks and may be best avoided. Travellers should take the most appropriate anti-malarial prophylaxis medication and be extra vigilant over measures to prevent mosquito bites.
| | ==[[Asplenia screening|Screening]]== |
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| The pneumococcal vaccinations may not cover some of the other strains of pneumococcal bacteria present in other countries. Likewise their antibiotic resistance may also vary, requiring a different choice of stand-by antibiotic.
| | ==[[Asplenia natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
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| ====Additional measures==== | | ==Diagnosis== |
| * ''Surgical and Dental procedures'' - Antibiotic prophylaxis may be required before certain surgical or dental procedures.
| | [[Asplenia diagnostic study of choice|Diagnostic study of choice]] | [[Asplenia history and symptoms|History and Symptoms]] | [[Asplenia physical examination|Physical Examination]] | [[Asplenia laboratory findings|Laboratory Findings]] | [[Asplenia electrocardiogram|Electrocardiogram]] | [[Asplenia x ray|X-Ray Findings]] | [[Asplenia echocardiography and ultrasound|Echocardiography and Ultrasound]] | [[Asplenia CT scan|CT-Scan Findings]] | [[Asplenia MRI|MRI Findings]] | [[Asplenia other imaging findings|Other Imaging Findings]] | [[Asplenia other diagnostic studies|Other Diagnostic Studies]] |
| * ''Animal bites'' - adequate antibiotic cover is required after even minor dog or other animal bites. Asplenic patients are particularly susceptible to infection by ''C. canimorsus'' and should receive a five day course of [[co-amoxiclav]] ([[erythromycin]] in patients allergic to penicillin).<!--
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| --><ref name="SHB2002-measures">{{cite web | title=Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen | url=http://www.shb.ie/Nonworddocs/hp/asplenia.pdf | format=PDF | year=2002 September | publisher=UK Southern Health Board}}</ref>
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| * ''Tick bites'' - ''[[Babesiosis]]'' is a rare tickborne infection. Patients should check themselves or have themselves inspected for tick bites if they are in an at-risk situation. Presentation with fever, fatigue, and haemolytic anaemia requires diagnostic confirmation by identifying the parasites within red blood cells on blood film and by specific [[serology]]. [[Quinine]] (with or without [[clindamycin]]) is usually an effective treatment.<!--
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| --><ref name="SHB2002-measures"/>
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| * ''Alert warning'' - Consider carrying a card, or wearing a [[Medical alert jewelry|special bracelet or necklet]] which says that you do not have a working spleen. This would alert a doctor to take rapid action if you are seriously ill and cannot tell them yourself.
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| ==References== | | ==Treatment== |
| {{Reflist|2}}
| | [[Asplenia medical treatment|Medical Therapy]] | [[TAsplenia surgical techniques|Surgery]] | [[Asplenia primary prevention|Primary Prevention]] | [[Asplenia secondary prevention|Secondary Prevention]] | [[Asplenia cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Asplenia future or investigational therapies|Future or Investigational Therapies]] |
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| {{Hematology}}
| | ==Case Studies== |
| {{Phakomatoses and other congenital malformations not elsewhere classified}}
| | [[Asplenia case study one|Case #1]] |
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